Owners of climate technology often face a situation where a smart humidifier stops responding to changes in the microclimate or shows incorrect data in the application. Finding the responsible element becomes a paramount task for diagnosing a malfunction. Understanding where the humidity sensor is located allows not only to check its purity, but also to exclude mechanical damage to the housing.
In Xiaomi and sub-brands like Deerma or Zhimi, the monitoring system is usually integrated directly into the design, but the visible part can vary. Most modern models use an external sensor that contacts the air directly, rather than being hidden deep inside the sealed unit, which is designed to quickly read changes in the atmosphere of the room.
If you notice that the device stopped turning off when you reach a given threshold or, conversely, ignores the dryness of the air, the problem may lie in this node, and then we will discuss in detail the design features of the various modifications and how to maintain them.
Design features of hygrostats in Xiaomi models
The company's engineering is focused on making concise devices, so the humidity sensor is often disguised as decorative elements. In classic ultrasonic models such as the Xiaomi Smart Air Humidifier (versions of CJXJSQ02ZM or CJSSQ01ZM), the sensor is located on the top panel, this is the area around the digital display or directly below it, where air circulates most freely.
But in non-display versions like the Xiaomi Mi Humidifier Pro, the situation is different: here, the hygroscopic sensor is often hidden under the top cover, but has direct access to the airflow through special perforations. It is important to understand that this is not just a "hole", but a technical hole leading to a sensitive element inside the case. In some cases, it requires partial disassembly, which is not recommended without loss of warranty.
Special attention should be paid to rotary-nozzle models, where the sensor can be shifted to the base or placed on the side of the sensor so that the steam jet does not fall directly on it. Direct contact with cold fog distorts the readings, causing the device to think that the humidity in the room is already 99%, and stop prematurely.
- 🔍 Top panel – a classic placement in models with a display.
- 💨 Side perforations - typical for models of the Pro and Lite series.
- 🌫️ Zone at the base - occurs in devices with 360-degree spraying.
- 📡 Integration into the database – some smart models bring the sensor to the base if it is removable.
⚠️ Warning: Never attempt to remove the sensor mechanically using sharp objects.The sensor element is covered with a protective mesh, damage to which will lead to irreversible failure of the electronics and loss of warranty.
Why can the sensor lie?
The hygrostat sensor is covered over time by a microscopic layer of dust or mineral plaque from water, which creates a barrier that slows down the response to changes in humidity, and the location of the device next to the battery or window can give a systematic error in readings.> To accurately determine the location, you need to know the specific model of your device. in the Xiaomi Smart Air Humidifier series 2 (MJJSQ04DY) The sensor is under the top cover, in a special recess next to the fragrance compartment, and it looks like a little black or white dot, sometimes closed by a fine mesh. DEM-F600 and DEM-F628, And these are often sold under the Xiaomi Youpin brand, and they have a sensor on the end of the shell, closer to the top of the tank. 3-5 mm. That's where air comes from, not steam from inside the tank. In premium models like the Xiaomi Smart Air Humidifier Pro, a more sophisticated system is used. Here, the electronic module can be combined with a temperature sensor. It's usually located at the top, but access to it is limited to the design of the lid. To clean these models, the manufacturer recommends using a soft brush without removing the protective gratings. It's worth noting that in compact models like the Xiaomi Mijia Humidifier Lite, there may be no separate visible hole at all, but it is more difficult to maintain such parts in the slit. Even if you know where the humidity sensor is, it doesn't guarantee perfect performance. The most common problem is pollution. Dust, pet hair, and a suspension of minerals from the water settle on the sensing element. This causes the device to "stick" at certain values. The second reason is the wrong positioning. If the humidifier is in the corner, behind the curtain or too close to the wall, the air circulation is disrupted. The hygrostat reads local humidity, which can be very different from the average in terms of the sensor, and sometimes the third-calibrex application to the grid or the wired device requires a third-shift to be switched to the computer. It is also worth checking whether the hole for air intake is closed with foreign objects. ☑️ Diagnosis of sensor malfunction Check for dust on the holes Change the place of installation of the humidifier Reset the device Compare the readings with an external hygrometer: 0 / 4 ⚠️ Warning: If the readings are unchanged after cleaning, the electronic component itself may have failed, in which case self-repair is impossible without soldering equipment and knowledge of circuitry. Maintenance of the humidity sensor requires a delicate approach. First, you need to completely turn off the device and drain the water. Never clean while the device is connected to the network, even if you do not touch the electrical contacts directly. Use a dry soft brush for drawing or makeup. Carefully walk the bristles through the holes where the supposedly hygroscopic element is located, which will help remove surface dust. If the contamination is more serious, you can use a cotton swab slightly moistened in distilled water, but in no case pour the liquid inside. To remove the mineral plaque (white plaque), you can use a cotton swab dipped in a weak solution of citric acid. After processing, be sure to wipe the place with a clean wet stick to remove the remaining acid, and let the device dry completely before turning on. 🧹 Use only dry or slightly wet tools. 🚫 Do not use aggressive household chemicals or alcohol. 💧 Use distilled water for the final wipe. ⏳ Allow the device to dry for at least 30 minutes before switching on. If you use distilled water to refill your humidifier, cleaning the sensor is extremely rare, usually no more than once every six months. Comparison of sensor locations across models. For convenience, we have prepared a composite table that will help you navigate the variety of models. Different generations of devices have their own design features, which will save time in search and maintenance. The device's positioning sensor Type Access Features Xiaomi Smart Humidifier 2 Under the top cover, near the button Open (via the grid) Sensitive to the direct pair Xiaomi Humidifier Pro Upper end Hidden perforation of the case Integrated with the display Deerma DEM-F600 Sideway, closer to the top Hole d=4mm Requires regular cleaning of the case (at the board) Without direct access Fence through the size of the parts As seen from the scenarios, the sensor is not the correct in the case of the humidity, but the upper part of the sensor is so easy to repair the device, but the above in the upper part of the s, it is the stroika, it is the way to the air. In Mi Home, you can create automations based on humidity readings, but if the sensor is not well positioned, the scripts will not work properly, for example, if you have the condition to turn on the humidifier, if the humidity is lower. 40%", The sensor is closed with a curtain, the device can turn on too often, so when setting up a smart home, it is important to consider the physical location of the device and its sensors relative to the sources of moisture and heat, and calibration is also available in some model settings. If you are sure that the hygrostat is showing incorrect data, check for firmware update. Sometimes the manufacturer releases updates that improve the algorithms for processing data from the sensor. ⚠️ Note: Do not set up automatic shutdowns when 100% This can cause condensation on furniture, the optimal shutdown threshold — 60-65%. Can you replace the humidity sensor yourself? This is theoretically possible if you find a compatible component in the radio parts market (often sensors like SHT20 or analogues). However, replacing it will require soldering and disassembly of the case, which is almost guaranteed to lead to loss of warranty. In addition, after replacement, software calibration may be required, available only to service centers. Why does the humidifier show 99% humidity immediately after switching on? Most likely, water or condensate has been hit on the humidity sensor. This often happens if the tank was not installed until the end or the device was transported horizontally. You need to turn off the device, remove the tank, extract the tank, the tank, can give the sensor a few scenters to use the s, can give the sensors, the scenters a sing the sensing the scenter, can cause the sensor to sensing the sensor to detector to sensing the sensing the device to scenter to sensing the device to scenter, or to scenter. If you use aroma capsules, try not to place them directly above the air intake hole, if the design allows, and more often do preventive cleaning. How often do you need to calibrate the sensor? Officially, calibration is not required. However, if you notice a difference in readings with reality by more than 10-15%, it is worth cleaning the sensor. If this does not help, you can try to reset the device to factory settings through the application, but mechanical calibration in a household environment is impossible.